JP5912033B2 - Paper towel manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a paper towel used for wiping liquid such as wiping water after washing hands .

Paper towels are required to be able to wipe off water and other liquids in a short time after washing their hands in a kitchen, a restroom or the like.
However, in the conventional paper towel, either the water absorption speed or the water absorption amount is not satisfactory, or the water once wiped off at the time of wiping may ooze again. In addition, it may be difficult to feel that water has been completely wiped off due to such slow bleeding and water absorption speed, and two or three sheets have been used in one wiping operation.

  On the other hand, paper towels are disposable products that are rolled up after use and thrown into a trash can provided in a toilet or the like. However, the conventional paper towel spreads quickly even if it is strongly rolled and discarded in the trash can, and it is practically only 20-30% compressible, and the trash can fills up quickly and the paper towel in the trash can many times. Needed to be recovered.

Japanese Patent No. 3838155 JP 2002-235299 A

  Then, the main subject of this invention is providing the paper towel which has the outstanding water absorption more than before, and can be made compact and discarded, without spreading when rounded at the time of disposal.

The present invention that has solved the above problems and the effects thereof are as follows.
<Invention of Claim 1>
A wet paper forming process in which a papermaking material is discharged onto a long web to form a wet paper;
A dehydration step of dehydrating the wet paper in the process of transporting the wet paper through the long net,
A pressing step of pressing a press roll in multiple stages against the wet paper that has undergone the dehydration step;
A felt transporting process for transporting the wet paper that has been squeezed in the pressing process after being transferred to the transport felt;
A wet crepe application step in which the wet paper transported on the transport felt is transferred to a roll and the wet paper on the roll is peeled off by a blade to apply a wet crepe, and is transferred onto a bulky wire;
A transition step of pressing the wet paper on the bulky wire against the Yankee dryer and transferring it onto the Yankee dryer;
A drying process in which the wet paper transferred to the Yankee dryer adheres to the surface of the Yankee dryer and is transported and dried;
A dry crepe applying step of peeling dry paper dried on a Yankee dryer with a blade and applying a dry crepe,
Performing the wet crepe application and the dry crepe application online;
A method for producing a paper towel.

<Invention of Claim 2>
The method for producing a paper towel according to claim 1, wherein the sum of the crepe rate at the time of wet crepe application and the crepe rate at the time of dry crepe application is 10 to 40%.

<Invention of Claim 3>
The method for producing a paper towel according to claim 2, wherein the crepe rate at the time of applying the dry crepe is 5 to 20%, and the crepe rate at the time of applying the wet crepe is 5 to 20%.

<Invention of Claim 4>
The manufacturing method of the paper towel of any one of Claims 1-3 which used the top felt at the time of transferring a wet paper to a Yankee dryer as a bulky wire.

<Invention of Claim 5>
The paper towel manufacturing method according to claim 4, wherein a mesh of the bulky wire is 10 to 50 mesh (line / inch).

<Reference invention 1>
A paper towel manufactured by the method for manufacturing a paper towel according to any one of claims 1 to 5 ,
US basis weight is 15-50 g / m ² , paper thickness is 238-500 μm,
A paper towel having a density of 0.060 to 0.142 g / cm ³ .

<Reference invention 2>
The paper towel of the above-mentioned reference invention 1 , wherein the aspect ratio of the dry tensile strength is 0.8 to 1.5.

(Function and effect)
Conventionally, paper towels have been manufactured by making paper with a circular paper machine and applying either wet crepe or dry crepe before and after the Yankee dryer.
However, with this conventional manufacturing method, it has been difficult to sufficiently improve the water absorption and water absorption speeds required for paper towels and the compactness at the time of disposal.

  In the present invention, wet crepe application and dry crepe application, which are not conventionally used in the manufacture of sanitary thin paper such as paper towels, are performed in this order online at a predetermined crepe rate. The inter-fiber voids in the interior of the paper towel were increased and dense, the irregularities on the surface of the paper towel were increased, and the porous structure of the paper towel and the uniformity of the fiber orientation were improved.

  That is, according to the paper towel manufacturing method of the present invention, a paper towel having low density and excellent “porosity” and “three-dimensional liquid penetration isotropy in the thickness direction on a flat surface” is manufactured. . Paper towel that does not spread even when it is rolled up when it is supple because it excels in water absorption rate and water absorption speed, and once absorbed water is difficult to bleed out due to its excellent “porosity” and “isotropy of liquid penetration” It becomes.

  In the present invention, the wet crepe application and the dry crepe application online means that both crepe application processes are performed during a series of paper making to form dry paper from the paper making raw material. The application of dry crepe application, wet crepe application, or both in a separate process from the papermaking process is an off-line application. By performing each crepe application online, the paper towel according to the present invention can be manufactured particularly effectively and with high productivity.

  In the present invention, for example, the aspect ratio of the product is set to 0.8 to 1.2 by adjusting the balance between the speed at which the raw material is injected from the inlet and the wire speed by using a long net paper machine. As a result, the fiber orientation of the product can be made substantially equal in the MD direction and the CD direction.

Here, a more specific effect of the production method of the present invention will be described. In the conventional paper towel, even after hand washing, the paper quality is 40 g / m ² or more, the paper thickness is 155 μm or more, and the water absorption is 150 g / m ² or more. The water could not be sufficiently wiped off during the wiping operation, and it was necessary to use 2 to 3 sheets. With the paper towel according to the manufacturing method of the present invention, the rice basis weight was as low as 30 g / m ^2. In addition, it is possible to obtain a paper towel that can have a paper thickness of 238 μm or more, can secure a water absorption exceeding 170 g / m ^2, and can sufficiently wipe off water even with one sheet. In addition, the paper towel manufactured by the present invention does not spread after being rolled up at the time of disposal, is maintained at a volume of about 50%, and compactness at the time of disposal is also achieved. In the present invention, the paper thickness can be increased by about 70% and the density can be reduced by about 50% with the same US basis weight as compared with the conventional method. Further, the amount of water absorption can be increased by about 25%, and the water absorption speed can be increased by 1 second or more.

  Here, in the present invention, it is desirable to increase the beating degree of the papermaking raw material preferably to 460 cc to 560 cc (CSF) so that the fiber is fibrillated and the surface area of the fiber is increased.

  According to the present invention as described above, there is provided a paper towel which has excellent water absorption and can be made compact and discarded without spreading when rolled up at the time of disposal.

It is the schematic of the manufacturing process of the paper towel of this invention. It is the schematic which shows from the wet crepe provision process of the manufacturing process of the paper towel of this invention to the dry crepe provision process. It is sectional drawing of the bulky wire concerning this invention.

Next, an embodiment of the present invention will be described in detail below with reference to FIG. FIG. 1 is a schematic view of a long net papermaking facility X1 that is preferable for carrying out the paper towel manufacturing method of the present invention.
In the present embodiment, a wet paper web forming process P1 for discharging the papermaking raw material onto the long net 10 to form the wet paper web W1, and a dehydrating process for dehydrating the wet paper web in the course of transporting the wet paper web W1 by the long net 10. P2, the pressing process P3 that presses the press rolls 20A and 20B against the wet paper W2 that has undergone the dehydration process P2, and the wet paper W3 that has been squeezed in the pressing process P3 is transferred to the transport felt 30 and then transported. The felt transporting process P4 and the wet paper W4 transported on the transport felt 30 are transferred to a roll, and the wet paper W5 on the roll is peeled off by the blade 40 to be wet creped, and also transferred onto the bulky wire 50. Wet crepe application process P5 and wet paper W6 on the bulky wire 50 are pressed against the Yankee dryer 60 and transferred onto the Yankee dryer 60. The transfer process P6 to be performed, the drying process P7 to transfer the wet paper transferred to the Yankee dryer 60 while being attached to the surface of the Yankee dryer 60, and the dry paper dried on the Yankee dryer 60 to be drawn by the blade 61. And a dry crepe application process P8 for peeling and applying a dry crepe. Hereinafter, each process etc. are explained in full detail.

  First, the papermaking raw material which concerns on this invention is demonstrated. The papermaking raw material according to the present invention is prepared by adding an appropriate agent or the like to pulp slurry. In the present invention, pulp obtained by mixing softwood pulp and hardwood pulp, or used paper pulp is preferably used as a pulp raw material that is a main raw material for papermaking. The softwood and hardwood pulps may be bleached or unbleached. Further, a mixture of unbleached unbleached pulp and bleached pulp may be used. When conifer pulp and hardwood pulp are mixed and used, it is preferable to contain 60 to 95% of conifer pulp and 5 to 40% of hardwood pulp. Softwood-derived pulp has a long fiber length and fiber orientation in the papermaking stage tends to be in a predetermined direction, and a difference in the peel strength aspect ratio tends to occur. However, softwood-derived pulp is 60 to 95%, and hardwood-derived pulp is 5 to 5. When the blending ratio is 40%, it becomes difficult to produce a difference in the aspect ratio of the peel strength due to the presence of hardwood derived pulp. Furthermore, since the fiber length of the hardwood-derived pulp is short, the fibers become dense and the flexibility is improved.

  In addition, the pulp derived from the coniferous tree suitably used in the present invention has a fiber thickness (width) of 30 to 40 μm and an average fiber length of about 2.5 to 5 mm.

  Here, it is desirable that the papermaking raw material in the present invention has a freeness of 460 cc to 560 cc (CSF: Canadian Standard Freeness) by a beating operation. This numerical value is slightly higher than the numerical value when manufacturing a general paper towel. Increasing the CSF means that the fibrillation of the pulp fiber is promoted, and the fibrillation of the pulp fiber improves the surface area of the pulp fiber constituting the paper towel, thereby improving the water absorption. Here, such a high CSF papermaking raw material has a problem that it is difficult to dehydrate. However, if papermaking is performed using a papermaking facility with an improved long net system as in this embodiment, the dewaterability derived from the high CSF can be obtained. Can improve the effects of deterioration.

  A known additive can be appropriately added to the papermaking raw material. In the present invention, additives preferably used are wet paper strength agents and dry paper strength agents. The wet paper strength agent should be added in an amount of 5.0 to 20.0 kg / pulp t in the papermaking raw material, and the dry paper strength agent should be added in the amount of 5.0 to 20.0 kg / pulp t in the papermaking raw material. desirable. Use of these paper strength agents facilitates adjustment to a desired paper strength.

  Further, each step and each facility of the paper making process according to the present invention will be described. In the present embodiment, the improved paper web equipment X1 illustrated in FIG. 1 is used, and the papermaking material is first discharged from the inlet 1 onto the web 10 to form the wet paper W1 (wet paper formation). The process P1, this process, and the subsequent dehydration process may be collectively referred to as a wire part). Then, the wet paper is dehydrated (dehydration process) on the long net 10.

  Compared with paper making using a circular net paper making machine, paper making by the long net type paper making equipment X1 is dehydrated over time in the process of being conveyed by the long net paper making machine 10, so that the decrease in the volume of the paper towel is reduced. As a paper towel structure, the gap between pulp fibers can be increased. Furthermore, the specific volume of the paper towel can be increased, and the dewatering of the high CSF papermaking raw material that has been further fibrillated can be sufficiently performed.

  Here, the dewatering time by the long net 10 is preferably about 0.1 to 18 seconds. In this case, it is desirable that the conveyance length by the long net is approximately 5 to 30 m in relation to the manufacturing time.

  Further, in the papermaking by the long-mesh type papermaking equipment X1, since the papermaking raw material is discharged from the inlet 1 onto the long web 10, unlike the mode in which the papermaking raw material is scooped up into the net like a circular net, the fiber orientation is longitudinally and laterally and Differences hardly occur in the thickness direction of the paper layer. For this reason, it becomes possible to manufacture a paper towel that has a high water absorption rate and is flexible and difficult to spread when rounded at the time of disposal.

  Here, in the dehydration step P2, the moisture contained in the wet paper web W1 on the long net 10 is naturally dropped or sucked down through the long net and dehydrated.

The press process P3 performed subsequent to the dehydration process P2 is a process of pressing the press rolls 20A and 20B and pressing the wet paper W2 on the long net 10 that has undergone the dehydration process P2 further downstream. . In this embodiment, preferably, when the wet paper web W2 on the long net 10 is transferred to the transporting felt 30 at the subsequent stage, the press rolls 20A and 20B are pressed to perform squeezing. The pressing pressure is an appropriate adjustment item, but is preferably 1.0 to 6.0 kg / cm ² .

  In this embodiment, it is desirable to press the press roll in a plurality of stages, and more preferably, the press roll is pressed three times or more. The multi-stage press can reduce the press pressure per time and can prevent a decrease in the bulk of the manufactured paper towel, and the paper towel can be suitably made porous. Note that the low-pressure multi-stage press is effective in preventing the decrease in bulk due to the action of water equalizing in the wet paper after the press by the capillary action of the fiber and the action of restoring the fiber in the thickness direction. .

  In the illustrated example, a form in which pressing is performed twice is shown. A center roll 21 is provided between the transport path formed by the long net 10 and the felt transport path 30 at the subsequent stage. One press roll is provided on the long net side and one press roll is provided on the felt transport path side. 20A and 20B are arranged. Squeezing is performed between the press rolls 20 </ b> A and 20 </ b> B and the center roll 21. The wet paper web W2 that has been conveyed on the long net 10 is picked up and transferred to the first-stage press roll 20A (press roll on the long net side), pressed between the center roll 21 and picked up by the center roll 21. Is then transferred to the second press roll 20B (press roll on the felt conveyance path side), picked up by the second press roll 20B, transferred, and then fed from the second press roll 20B. It is shifted to the road 30. A known suction technique is used for transferring the wet paper to each roll. In addition, each press roll does not directly contact the wet paper, but is actually wound around the press roll and contacted via the endless conveyance path.

  The wet paper web W3 transferred to the felt transport path 30 through the pressing process P3 is felt transported in the felt transport process P4. The felt conveyance path 30 has a smoother surface than the long mesh 10, has excellent adhesion to the wet paper, and has a good surface texture. Here, the conveyance felt 30 itself may have water absorption or may not have water absorption. However, if it has water absorption, the adhesiveness with the conveying felt 30 is increased and the formation is good, and the press pressure in the dehydration process P2 and the press process P3 can be reduced, and the bulk is increased. Can be further prevented.

  In the present invention, considering the natural drying of the wet paper W3, the uniformization of moisture in the wet paper, and the adhesion with the transport felt 30, the transport time by the transport felt 30 is 0.5 to 30 seconds, and the transport length is It is desirable to be 15-50 m.

  As shown in FIG. 2, the wet paper web W4 whose water content has decreased moderately through the predetermined felt transport P4 is picked up from the appropriate felt transport path 30 to the appropriate press roll 54, and then wet crepe application step P5. Then, it is peeled off from the press roll 54 by the blade 40 and wet creped.

  The wet crepe is creped in the state of the wet paper W5. That is, the wet paper web W5 is dried in a subsequent process. For this reason, even if the wet crepe absorbs water, the crepe does not easily stretch or collapse. In the present invention, the wet crepe action maintains the fiber orientation during water absorption and the surface structure formed by the bulky wire 50, which will be described later, without collapsing, thereby improving water absorption by low density porous properties. In addition, once the water has been absorbed, it becomes a paper towel in which it is difficult for the water to ooze out again.

  Here, the preferable crepe rate at the time of wet crepe provision in this invention is 5 to 20%. If the crepe rate is less than 5%, the effect of water absorption is small, and the bulk is difficult to come out. If it exceeds 20%, the tensile strength in a wet state is lowered and the flexibility is lowered.

  In this embodiment, the crepe rate can be calculated as follows. Crepe rate: {(peripheral speed of press roll) − (transport speed of bulky wire)} / (peripheral speed of press roll) × 100. In addition, when providing a suitable conveyance roll and conveyance path in the front | former stage of a bulky wire, the said "the conveyance speed of a bulky wire" shall be the speed of this conveyance roll or a conveyance path.

  The wet paper W6 to which the wet crepe has been applied is then transferred onto the bulky wire 50 and transferred onto the Yankee dryer 60 via the bulky wire 50. In this transition, the bulky wire 50 is moved so as to be pressed against the Yankee dryer 60.

  As shown in the cross-sectional view of FIG. 3, the bulky wire 50 is knitted with warp yarns 50T and weft yarns 50Y and has fine regular irregularities in a mesh pattern on the surface. In addition, regular density is generated according to the unevenness of the surface of the bulky wire 50. When this coarse / dense structure is formed, a double structure is formed in which the liquid is quickly absorbed in the sparse part and the liquid is absorbed over time in the dense part. Further, regular irregularities on the surface of the bulky wire 50 are transferred to the surface of the wet paper web W6. The unevenness on the surface improves the sheet surface area and improves the liquid absorption. Further, when the uneven pattern is a pattern that is vertical and horizontal and has no deflection, the spread of moisture on the surface of the paper towel is spread evenly in a plane. Therefore, such a bulky wire is preferably a pattern in which the uneven pattern is vertical and horizontal and has no deflection.

  In the present invention, it is preferably performed by pressing the Yankee dryer with one touch roll. By using one touch roll 55, it is possible to suitably modify the internal structure and the surface structure of the paper towel of the bulky wire 50, and to prevent a decrease in bulk.

  Here, when a suitable thing as the bulky wire 50 used by this invention is illustrated, the mesh is 10-50 mesh (line / inch), and the thickness of the wire which comprises the bulky wire 50 is about 0.5 mmphi. . Note that the unevenness difference (the difference between the top and bottom) of the wet paper provided by the bulky wire 50 is desirably 0.4 to 1.0 mm. This can be adjusted by the surface configuration of the bulky wire 50, the contact pressure to the Yankee dryer 60, the thickness of the wet paper web W6, the moisture content, and the like.

  In this way, by transferring the wet paper W6 to the Yankee dryer 60 through the bulky wire 50, the layer structure of the fibrillated fiber is provided with irregular shapes in a regular and uniform orientation in a plane, and the sheet layer structure Therefore, an excellent effect of improving water absorption can be obtained. In addition, by adding appropriate irregularities to the front surface of the sheet in contact with the mirror surface of the dryer by the bulky wire 50, there is an effect of making the characteristics of the front surface of the sheet and the back surface the same.

  In addition, the effect | action by this bulky wire is more effective when the above-mentioned fiber thickness (width) is 30-40 micrometers as a papermaking raw material, and the pulp derived from conifers whose average fiber length is about 2.5-5 mm is used. The inventor knows. In this embodiment, the bulky wire is used. However, in the present invention, it is not always necessary to use the bulky wire, and a normal felt can be used.

  The wet paper web W6 transferred to the Yankee dryer 60 is dried in the process of adhering to the surface of the Yankee dryer and transported, and then peeled off from the Yankee dryer 60 by the blade 61, and after appropriate winding processes, the paper towel according to the present invention. It is referred to as base paper T. The paper towel according to the present invention can be obtained by appropriately cutting the paper towel base paper.

  Here, in the present invention, when the sheet W6 is peeled off from the Yankee dryer 60 by the blade 61, a dry crepe is applied. By applying the dry crepe, the elongation and flexibility are improved, and it becomes difficult to spread again especially when rounded at the time of disposal. Since the dry crepe is particularly stretched during water absorption, the production method of the present invention acts to expand the water absorption area due to the elongation of the dry crepe during water absorption, and the water absorption by the structure provided by the previous wet crepe and the bulky wire. Since the effects such as the properties are exhibited, the water absorption amount and the water absorption speed are particularly improved, and the water once absorbed is difficult to exude again.

  In the present invention, the wet crepe application step P5 and the transition step P6 using the bulky wire have irregularities on the surface of the sheet W6, and the adhesion to the Yankee dryer is reduced, so that it is difficult to apply dry crepes. However, if the sum of the crepe rate at the time of applying the wet crepe and the crepe rate at the time of applying the dry crepe is 10 to 40%, both wet crepe application and dry crepe application can be sufficiently performed. Moreover, if it is the said 10 to 40% of range, the paper towel from which a desired effect will be acquired can be manufactured.

  In addition, since the preferable crepe rate at the time of wet creping is 5 to 20% as described above, the preferable crepe rate at the time of applying the dry crepe is 5 to 20%. When the crepe rate at the time of applying the dry crepe is less than 5%, the effect of improving the flexibility is small and the bulk is difficult to be produced. Further, in the present invention, as described above, it may be difficult to apply a dry crepe, and application of more than 20% is difficult in production.

  In this embodiment, the crepe rate at the time of applying the dry crepe can be calculated as follows. Crepe rate: {(peripheral speed of Yankee dryer) − (conveying speed of dry paper T)} / (peripheral speed of Yankee dryer) × 100.

  In addition, in applying the wet crepe and the dry crepe in the present invention, it is more preferable that the crepe rate at the time of applying the wet crepe and the crepe rate at the time of applying the dry crepe are 1: 1 to 1: 0.5.

  In addition, although the example which manufactures the manufacturing method of this invention by the long-mesh papermaking equipment of FIG. 1 was described above, this invention is not limited to this embodiment. For example, it is also possible to use an improved circular net paper machine in which a wet crepe is applied in front of a Yankee dryer and a dry crepe can be applied when peeling from the Yankee dryer.

  Subsequently, the preferable physical property of the paper towel manufactured by the manufacturing method of the above-mentioned this invention is demonstrated.

First, in the production method of the present invention, kitchen paper having a weight of 10 to 80 g / m ² can be produced, but the preferred weight of the paper towel that can effectively obtain the desired effect of the present invention is 15 to 50 g / m ^2. m ² , preferably 15 to 35 g / m ² . The paper thickness is 238 to 500 μm, and the preferred paper thickness is 238 to 330 μm. Thus, density was 0.080~0.142g / cm ^3, preferably 0.095~0.142g / cm ^3. Compared with a general paper towel, this is a thick and low-density paper per tsubo. And if it is in this range, the paper towel according to the present invention has the effect that it wants to obtain, that is, it has excellent water absorption, it is difficult for the water that has been absorbed once to bleed out again, and the compactly rounded state is maintained at the time of disposal. It becomes like this.

  On the other hand, in the production method of the present invention, the aspect ratio of the dry tensile strength can be adjusted to 0.9 to 1.5, but the preferred aspect ratio of the dry tensile strength of the paper towel according to the present invention is 0.8 to 1.5. Preferably it is 0.8-1.2. The moisture absorption orientation is greatly influenced by the fiber orientation in the thickness direction of the sheet. In the present invention, since the fiber orientation in the thickness direction of the sheet is uniform as compared with the conventional paper towel, the orientation of the fibers in the sheet plane direction is substantially equal in aspect ratio so as not to hinder this. It is desirable to do. If it does in this way, since the absorbed water spreads circularly on the sheet plane, the area that spreads over the elapsed time is maximized and the water absorption speed is fast. This can be achieved by using the papermaking raw material and a long paper machine.

  The water absorption speed is 5 seconds or less, more preferably 3.8 to 5 seconds. If it is 5 seconds or less, it is possible to quickly absorb moisture at the time of water wiping operation sufficiently after hand washing. Here, the water absorption rate according to the present invention is a value obtained by dropping 10 μl of distilled water onto the sample surface in accordance with the water absorption test of JIS P 3104 and measuring the time until no shine occurs. Whether or not there is no light is judged by visual observation, and the dropping surface is a surface that is in contact with the felt surface in the felt conveying step. One test piece is measured five times, and the average value is taken as the measured value.

[Test example]
Next, since various physical properties were tested for the paper towel of the manufacturing method according to the present invention and the paper towel (comparative example) of the conventional wet crepe only or dry crepe manufacturing method, the results are shown in Table 1 below. In the table, (-) means unknown or 0. Each test and evaluation are as follows.

[US tsubo]
It measured according to JIS P 8124 (1998).

[Paper thickness]
It shall be measured using a dial thickness gauge (thickness measuring instrument) “PEACOCK G type” (Ozaki Seisakusho) under the conditions of JIS P 8118 (1998). Specifically, confirm that there is no dust or dust between the plunger and the measurement table, lower the plunger on the measurement table, move the memory of the dial thickness gauge to adjust the zero point, Raise the plunger and place one sample on the test table. Slowly lower the plunger perpendicular to the paper surface and read the gauge at that time. At this time, only the plunger is placed. The terminal of the plunger is made of metal so that a plane with a diameter of 10 mm is perpendicular to the plane of the paper, and the load at the time of measuring the paper thickness is about 70 gf. The paper thickness is an average value obtained by performing measurement 10 times.

[density]
Value obtained by dividing the paper thickness [μm] by the rice tsubo [g / m ² ] [g / cm ³ ]

[Water absorption]
The amount of water absorption is based on the following measurement. The test piece is cut into a square of 100 mm length × 100 mm width and weighed. Next, distilled water is added to the pan so that the depth is 20 mm. A test piece is placed on a net of 135 mm length × 135 mm width (mesh 15 mm × 15 mm), placed in distilled water of a pan and immersed on the paper surface of the test piece, then the net is pulled up and held for 30 seconds to hold water. Cut it. Thereafter, the weight of the test piece is measured. One test piece is measured five times, and the average value is taken as the measured value.

[Water absorption speed]
In accordance with the water absorption test of JIS P 3104, 10 μl of distilled water was dropped on the sample surface, and the time taken until no shine was measured. Whether or not there is no light is judged by visual observation, and the dropping surface is a surface that is in contact with the felt surface in the felt conveying step. One test piece is measured five times, and the average value is taken as the measured value.

[Reverse (exudation)]
The test piece is cut into a length of 230 mm and a width of 210 mm, folded in the horizontal direction and placed on the bat. Measuring paper (Daio Paper Co., Ltd. (Elver Eco Smart) is folded in four and weighed. 500 μl of distilled water is dropped into the center of the test piece, and 3 seconds after the start of dropping, the measuring paper and the diameter of 80 mm, Place a weight of 59g in a cylindrical weight for 2 seconds on the dropping position with the measuring paper down (test piece side), and then immediately measure the weight of the measuring paper. The surface in contact with the felt surface is measured five times for each test piece, and the average value is taken as the measured value.

[Compressibility]
A test piece is cut into a length of 115 mm × width of 60 mm, and a plastic plate having a length of 245 mm × width of 127 mm, a weight of 30 g, and a thickness of 1 mm is placed on 100 sheets, and the heights of the four corners of the uppermost test piece are measured. Next, evenly put water on the entire test piece, place it on the bat, place the plastic plate again, place a columnar weight with a diameter of 165 mm, a height of 280 mm, and a weight of 5 kg in the center, Measure the height of the four corners of the specimen. The value obtained by subtracting the height after water is added from the height before water is included is taken as the measured value. Three measurements are taken, and the average value is taken as the measurement value.

From the result of Table 1, the paper towel (Example) by the manufacturing method of this invention has a low density, a large amount of water absorption, and a high water absorption speed compared with a comparative example. Also, based on the result of the reverse (bleeding out) test, the water once absorbed is difficult to ooze out. Furthermore, it is excellent in compressibility. More specifically, as for the paper thickness, the comparative example is 135 to 200 μm, while the embodiment of the present invention can increase the thickness by 238 to 330 μm, approximately 72%. In addition, the density of the comparative example is 0.154 to 0.319 g / cm ³ , while the density of the embodiment of the present invention can be reduced by approximately 50% to 0.095 to 0.142. Yes. Also, the amount of water absorption is 140 to 167 g / m < ² > in the comparative example, while the example of the present invention is improved by 174 to 208 g / m < ² >, approximately 25%. Further, the water absorption speed is 3.8 to 5 seconds, which is 1 second or more faster than the comparative example of 6 to 19 seconds. Further, the amount of reversal is much smaller than that of the comparative example.

  From the above, by applying the wet crepe and dry crepe according to the production method of the present invention, it is possible to wipe off the moisture adhering to the hand after hand washing firmly in a short time, less reversal of the moisture once absorbed, Furthermore, it is found that a paper towel can be manufactured that is not bulky and difficult to restore even after treatment.

  X1 ... long net papermaking equipment, 1 ... inlet, 10 ... long net, W1-W6 ... wet paper, T ... paper towel base paper, P1 ... wet paper forming process, P2 ... dehydration process, P3 ... press process, P4 ... felt transport process , P5 ... wet crepe application process, P6 ... transition process from bulky wire to Yankee dryer, P7 ... drying process, P8 ... dry crepe application process, 20A, 20B ... press roll, 21 ... center roll, 30 ... transport felt (felt) Transport path), 40 ... blade, 50 ... bulky wire, 55 ... touch roll, 54 ... press roll, 60 ... yankee dryer.

Claims (5)

A wet paper forming process in which a papermaking material is discharged onto a long web to form a wet paper;
A dehydration step of dehydrating the wet paper in the process of transporting the wet paper through the long net,
A pressing step of pressing a press roll in multiple stages against the wet paper that has undergone the dehydration step;
A felt transporting process for transporting the wet paper that has been squeezed in the pressing process after being transferred to the transporting felt,
A wet crepe application step in which the wet paper transported on the transport felt is transferred to a roll and the wet paper on the roll is peeled off by a blade to apply a wet crepe, and is transferred onto a bulky wire;
A transition step of pressing the wet paper on the bulky wire against the Yankee dryer and transferring it onto the Yankee dryer;
A drying process in which the wet paper transferred to the Yankee dryer adheres to the surface of the Yankee dryer and is transported and dried;
A dry crepe applying step of peeling dry paper dried on a Yankee dryer with a blade and applying a dry crepe,
Performing the wet crepe application and the dry crepe application online;
A method for producing a paper towel.   The method for producing a paper towel according to claim 1, wherein the sum of the crepe rate at the time of wet crepe application and the crepe rate at the time of dry crepe application is 10 to 40%.   The method for producing a paper towel according to claim 2, wherein the crepe rate at the time of applying the dry crepe is 5 to 20%, and the crepe rate at the time of applying the wet crepe is 5 to 20%.   The manufacturing method of the paper towel of any one of Claims 1-3 which used the top felt at the time of transferring a wet paper to a Yankee dryer as a bulky wire.   The paper towel manufacturing method according to claim 4, wherein a mesh of the bulky wire is 10 to 50 mesh (line / inch).

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